PubMed · 1070067
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
J Melcer. [Do fillings using composite resins represent progress?].. https://pubmed.ncbi.nlm.nih.gov/1070067/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
The purpose of this study was to evaluate the feasibility of aspartic acid derivative, N-acryloyl aspartic acid (N-AAsp) when used as a self-etching primer prior to the application of a commercial bonding agent containing 10-methacryloxydecyl dihydrogen phosphate. N-AAsp was synthesized by the reaction of DL-aspartic acid and acryloyl chloride. N-AAsp can be dissolved in water up to 25 wt % and can adequately remove the smear layer. When 20 wt % N-AAsp was applied as a self-etching primer, the tensile bonding strength of resin composite to dentin doubled to 16.0 MPa compared with that of the nonetching group or the 40 wt % H(3)PO(4) etching/water rinse group. Scanning electron microscopic observations revealed that the formation of the hybrid layer at the interface between the resin composite and dentin and the thickness of the hybrid layer increased with N-AAsp concentration. The hybrid layer in the specimens treated with 20 wt % N-AAsp aqueous solution presented a uniform structure, whereas those treated with 5 wt % N-AAsp solution showed a porous structure. We conclude that 20 wt % N-AAsp aqueous solution has good potential value as a self-etching primer.
Atomic force microscopy (AFM) has been used to determine microstructural changes, etching rates of peritubular dentin, and intertubular dentin recession during demineralization in dilute acidic solutions. These studies have not included many forms of altered dentin, including noncarious sclerotic root dentin associated with Cl V (abfraction) lesions. We sought to determine microstructural changes and recession rates during demineralization in citric acid (pH 2.5, 0.018M) for the transparent/sclerotic zone. Highly polished dentin disks were prepared from teeth with noncarious C1 V lesions (n = 3) and compared with normal root dentin (n = 3). Samples were etched at 5-s intervals for 1 min and at longer intervals up to 30 min. The depth changes in various portions of the dentin with respect to the reference layer were measured and changes in microstructure observed in solution in the wet cell of the AFM. In sclerotic dentin, most tubule lumens were occluded with crystalline deposits that etched more slowly than the other dentin components, but etching rates could not be determined due to their irregular geometry. The intertubular dentin recession quickly reached a plateau after a depth change of <1 microm for all dentin types, in agreement with prior work. Mixed linear regression models indicated an important difference between the etching of sclerotic intertubular dentin and that of non-sclerotic root dentin that became apparent after 600 s (p = 0.037). The sclerotic intertubular dentin underwent less depth change at the plateau (558 nm) compared to normal root dentin (744 nm). In addition, normal root dentin underwent significantly greater recession than coronal dentin (p = 0.002). The results of this study indicate that intertubular sclerotic dentin from Cl V lesions etches differently than normal root dentin, and this may help explain the difficulties in restoring such lesions with current bonding procedures.
BACKGROUND AND OBJECTIVE: The purpose of this study was to evaluate sealant shear bond strength on bovine enamel with standard acid etching compared with CO(2) laser etching. STUDY DESIGN/MATERIALS AND METHODS: Bovine enamel was prepared either by acid or laser etching and divided into four experimental groups, either acid or laser-etched teeth with or without a primer. A gelatin capsule was used to place the sealant on the prepared enamel surface and the bond tested in shear. Also surface roughness was evaluated by using a surface analyzer and an atomic force microscope. RESULTS: Shear bond strength results were the following: acid etch = 8.8 +/- 3.8 MPa, acid etch with primer = 10.3 +/- 5.5 MPa, laser etch = 4.0 +/- 1.1 MPa, and laser etch with primer = 6.2 +/- 2.3 MPa. Analysis of variance statistical analysis found no significant difference in bond strength between the acid-etched groups. However, the laser-etched groups had significantly lower bond strengths from the acid-etched teeth. In addition, a significant difference was observed between the laser-etched groups, where the use of the primer helped to increase the bond strength of the sealants. The surface roughness was significantly greater on the laser-etched teeth at the microm level (by using a surface analyzer) from the acid-etched and the control specimens. No difference in roughness (by using an atomic force microscope) was observed at the nanometer level between the laser and acid-etched teeth. CONCLUSION: For these particular settings, the laser-etched teeth resulted in lower bond strengths to enamel and the use of a primer increased the bond strength for laser-etched teeth only.